As a Canuck in 1998–99, he registered career highs in games played (65), wins (20), and shutouts (6). His workload was cut in half the following season and he signed with the Pittsburgh Penguins prior to 2000–01. His stay in Pittsburgh lasted one season as he signed with the New York Islanders in the off-season. He would remain an Islander for the rest of his career, primarily as a backup to veteran Chris Osgood and then youngster Rick DiPietro.

Throughout his career, Snow was the target of the league office on several occasions over his goaltending equipment, in particular his shoulder pads, which opposing teams accused of violating league rules on size. According to former teammate Mike Peca, Garth Snow was one of the best trash-talkers around. "He's got such a wit and sense of humor like no other. Snow says things that will cut you without being rude or obnoxious." (The Hockey News, August 30, 2002). Snow was regarded as a respected leader both on and off the ice.

On July 18, 2006, Snow officially confirmed his retirement and was named General manager of the New York Islanders following Neil Smith's dismissal after 41 days on the job.[2] There was much criticism directed the Islanders way for firing a Stanley Cup-winning GM after such a short tenure in favor of Snow, who at the time of his hiring held no experience in management. Defenders of the organization pointed to Snow's Master’s Degree in Administration and Bachelor’s Degree in Business Administration from the University of Maine.[3]

In Snow's first season as GM, he earned praise for making moves to open up space under the salary cap and using the space to trade for Marc-André Bergeron, Richard Zednik and Ryan Smyth. Snow was named NHL Executive of the year for 2006–2007 by Sports Illustrated.[4] Snow also received a great deal of praise from commenters on XM Radio[5] and other reports for his organization's picks in the 2008 and 2009 entry drafts. In 2012, Snow reportedly offered all seven of the Islanders' draft picks - one in each round, including the fourth overall - to Columbus in exchange for the second overall pick. Columbus GM Scott Howson turned down the trade offer, and the Islanders ended up picking defenceman Griffin Reinhart at No. 4.[6]